Inspector Stephen Dennis said Ms Ristevski’s disappearance is still being treated as a missing person investigation but they had grave concerns for her welfare.
Ms Ristevski was last seen at her home about 10am on June 29 and she hasn’t used her phone or accessed her bank accounts since.
It is understood she went for a walk to get some fresh air after a heated discussion with her husband Borce.
The Maribyrnong River snakes behind Ms Ristevski’s home, while a Department of Defence facility sits on the other side.
There has been a wave of support on social media to find the popular dress shop owner.
“We’ve laughed together, dressed and undressed together, and shared our highs and lows,” friend Connie Johnson posted on the Love Your Sister Facebook page.
Police questioned Mr Ristevski last week over the disappearance and he has been released pending further inquiries.
Ms Ristevski is 160cm tall, with a slim build and shoulder length brown hair.
She was last seen wearing a black jacket and jeans and is known to frequent Taylors Lakes.
Police say her disappearance is out of character.